Note: Some white smoke may be present during cold start-up conditions when the engine is operating normally.
- Cold ambient air temperature
- Low jacket water coolant temperature
- Extended idle periods
- Low quality fuel
- Cylinder head gasket
- Inoperative air inlet heater (if equipped)
- Incorrect valve adjustment
- Incorrect fuel injection timing
- Misfiring cylinder
- Low cylinder compression
- Faulty fuel injection nozzle
When the ambient air temperature is cold, the cylinder temperature is cooler. Not all the fuel will burn in the cylinders. The fuel that does not burn comes out of the exhaust as white smoke. White smoke is normal in cold temperatures until the engine has reached normal operating temperatures. There will be less white smoke if No. 1 diesel fuel is used.
Low Jacket Water Coolant Temperature
If the jacket water coolant temperature is low the engine will produce white smoke. Ensure that the normal operating temperature for the engine is reached.
When an engine runs at idle speed for a long period of time, the cylinders cool and all of the fuel does not burn. Do not idle an engine for a long period of time. If long idle periods are necessary, use No. 1 diesel fuel.
Check the API of the fuel. Refer to Troubleshooting, "Fuel Quality".
Remove the radiator cap. Start the engine and look for air bubbles in the coolant. Bubbles in the coolant are a sign of probable leakage at the head gasket. Remove the cylinder head from the engine. Check the following areas for cracks:
- Cylinder head
- Cylinder liners
- Gasket surface of the cylinder block
- Cylinder head spacer plate
Use a new head gasket when the cylinder head is installed. Refer to the Specifications module for the proper bolt tightening sequence.
Check the air inlet heater for proper operation. Refer to Systems Operation, Testing And Adjusting, "3406C Diesel Truck Engine".
Check the valve adjustment and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting, "3406C Diesel Truck Engine".
Incorrect Fuel Injection Timing
Check the fuel injection timing and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting, "3406C Diesel Truck Engine".
If the engine is misfiring, refer to Troubleshooting, "Engine Misfires, Run Rough Or Is Unstable".
Inlet/exhaust valves or piston rings are leaking compression. Disassemble the engine and find the source of the leaks.
Faulty fuel injection nozzles will normally cause the engine to misfire which will cause the engine to run rough. Faulty fuel injection nozzles can also cause too much smoke even if the engine is running smoothly. Remove the fuel injection nozzles and check the fuel injection nozzles. Refer to Special Instruction, SEHS7292.